Analysis of aniridia patients for mutations in the PAX6 gene

Introduction: Aniridia represents a congenital ocular disorder with partial or complete iris hypoplasia. The disorder is associated with poor vision, glaucoma, corneal and lenticular opacities, ectopia lentis due to abnormal zonula fibers, as well as optic nerve and macular abnormalities. Aniridia m ay present as either hereditary or sporadic cases. Some of the sporadic cas es develop Wilms' tumor, frequently as part of the WAGR syndrome (Wilms' tu mor, aniridia, genitourinary abnormalities and mental retardation). PAX6, a candidate gene located on chromosome 11p13, is often mutated in aniridia p atients. The gene encodes a transcription regulatory protein. Method: Analysis of the PAX6 gene was done using PCR (polymerase chain reac tion), SSCP (single strand conformation polymorphism) and DNA sequencing. Results: In 13 of 20 aniridia patients a PAX6 gene mutation was found. Conclusion: The mutations result in a gene product with reduced function or a reduced PAX6 protein level. Molecular analysis of aniridia is also a val uable diagnostic tool for Wilms' tumor risk evaluation, as patients with pr oven PAX6 mutations - in contrast to cases with large deletions of the 11p1 3 region - are at no increased risk to develop Wilms' tumor.